In hospitals, clinics or field medical operations, intravenous (IV) tubes are regularly used in situations that necessitate selection of various specific IV flow-rates. Prior IV control systems tend to be either difficult to monitor and adjust accurately, or too complex, heavy, and expensive for many situations and locations.
Existing in-line pump-driven flow control systems are typically costly, complex, and/or heavy, and reply on a power source other than gravity. In-line pump systems exist that have complex control systems, for example, which compare the actual flow-rate to the desired flow-rate to produce error signals that are then utilized to adjust the actual flow-rate. Such complex devices are impractical for use in remote field situations where low cost and simplicity are important.
Another approach to flow control in an intravenous system is to provide a manifold having multiple connection points for tubing, with each connection point corresponding to a different flow rate. Such a connector may address the need for reduced cost but is complex to use. Further, such a connector may create a contamination risk, by exposing the fluid to the environment when the tube is moved from one manifold connection point to the next.
Flow adjustment in IV tubes has also been attempted by means of providing a folded IV tube and controlling flow by limiting the degree of unfolding of a folded IV tube. Such a system has the benefit of the flow control apparatus not being in-line, but such a system tends to be inaccurate and difficult to control.
A flow control system comprises a fluid conduit tube having a flexible or compressible wall defining an interior axial fluid passage, and a control device having a plurality of selector units moveable to press on the tube so that the selector units compress the tube to have a reduced-cross-section, thus, reducing flow through the axial fluid passage of the tube. The selector units preferably move inward toward the tube to an inward position that compresses the tube and outward to an outward position that releases the compressive force on the tube. The selector units are adapted so that, in their inward positions, they cause different amounts of flow restriction, thus, corresponding to different flow rate selections.
The flow control device may be adapted for flexible conduits that deliver fluids to various processes, both medical and otherwise. The preferred embodiment of the flow control device is particularly well-adapted for IV tubes, wherein there are typically a small number of standard flow-rates, and wherein it is important to minimize the contact of the fluid with valves or other equipment that might contaminate the fluid with microbes or chemicals. The preferred embodiment of the flow control device comprises a plurality of discrete adjustments, corresponding to the preferred or standard flow-rates for IV treatments.